This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-215024, filed Jul. 14, 2000, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a weather radar belonging to meteorological equipment for calculating the presence of water droplets and wind direction and velocity from reflected electromagnetic waves.
2. Description of the Related Art
Conventional weather radars are meteorological sensors that observe a distribution of water droplets from waves reflected from water droplets such as clouds or rain due to Rayleigh scattering. In particular, weather Doppler radars do not only observe a distribution of water droplets but also observe the moving speed of the water droplets based on Doppler components of the reflected waves, thus making it possible to calculate wind direction and velocity for a space containing the water droplets. Thus, the current weather radars can calculate the wind direction and velocity only from regions with water droplets present therein.
As described above, the conventional weather radars can calculate the wind direction and speed only in the presence of water droplets.
The present invention is provided to solve this problem, and it is an object thereof to provide a weather radar that can execute wind observations despite the lack of Doppler echoes from water droplets such as rain or clouds.
A weather radar according to the present invention has the following characteristic configurations:
(1) A weather radar for using an antenna that can control a beam direction to radiate a pulse beam and receive a reflected wave in order to observe a rain or cloud occurring region within a covered area based on a signal intensity of the reflected wave, the weather radar comprising Bragg scattering observing means for arranging a beam formed by the antenna, in an arbitrary direction and observing Bragg scattering-induced echo components based on a received signal of the reflected wave to thereby calculate a distribution of wind direction and velocity relative to the beam direction from a result of the observation.
(2) A weather radar for using an antenna that can control a beam direction to radiate a pulse beam and receive a reflected wave in order to observe a rain or cloud occurring region within a covered area based on a signal intensity of the reflected wave, the weather radar comprising Rayleigh scattering observing means for directing a beam formed by the antenna toward the rain or cloud occurring region and observing Rayleigh scattering-induced Doppler echo components based on a received signal of the reflected wave to calculate a distribution of wind direction and velocity based on a result of the observation, and Bragg scattering observing means for arranging the beam formed by the antenna, in an arbitrary direction and observing Bragg scattering-induced echo components based on the received signal of the reflected wave to thereby calculate a distribution of wind direction and velocity relative to the beam direction from a result of the observation.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.